کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5533280 | 1402112 | 2017 | 9 صفحه PDF | دانلود رایگان |
- The cypovirus capsid structure was resolved at 3.3-Ã
resolution using a 200-kV TEM.
- The criterion for particle image selection was proposed.
- The structure of RdRp complex within the capsid was resolved at 3.9-Ã
resolution.
- The conformational change of RdRp suggests that the RdRp might also function as an RNA helicase.
Single-particle cryo-electron microscopy (cryo-EM) allows the high-resolution structural determination of biological assemblies in a near-native environment. However, all high-resolution (better than 3.5Â Ã ) cryo-EM structures reported to date were obtained by using 300Â kV transmission electron microscopes (TEMs). We report here the structures of a cypovirus capsid of 750-Ã diameter at 3.3-Ã resolution and of RNA-dependent RNA polymerase (RdRp) complexes within the capsid at 3.9-Ã resolution using a 200-kV TEM. The newly resolved structure revealed conformational changes of two subdomains in the RdRp. These conformational changes, which were involved in RdRp's switch from non-transcribing to transcribing mode, suggest that the RdRp may facilitate the unwinding of genomic double-stranded RNA. The possibility of 3-Ã resolution structural determinations for biological assemblies of relatively small sizes using cryo-EM at 200Â kV was discussed.
Graphical Abstract407
Journal: Journal of Molecular Biology - Volume 429, Issue 1, 6 January 2017, Pages 79-87